1. Field of the Invention
The present invention relates to a spring body for a slide fastener and a slider having the spring body mounted thereon, and particularly, the invention relates to a spring body for a slide fastener and a slider with an automatic stop function having the spring body mounted thereon, whereby the slider is miniaturized, the material cost is reduced, and the exterior design is improved.
2. Description of the Related Art
Conventionally, a slider for a slide fastener provided with an automatic stop function is used in many cases, in which the automatic stop function stops the movement of a slider body in such a manner that, by operating a pull against the slider body for coupling and releasing tooth rows of a fastener chain, a pawl portion of a spring body made of a long and minute elastic metal platy material is engaged with a part of the tooth row of the fastener chain. A structural example of such a slider is disclosed, for example, in Japanese Patent Laid-Open Publication No. 10-127313 proposed by the present applicant in advance. In the slider disclosed in this publication, a front attaching post and a rear attaching post are built back and forth on the slider body, a projection piece portion is protruded on a top surface of the front attaching post, a pawl hole is formed on the front side of the rear attaching post and a pull guide surface is inclined downwardly step by step toward the front side in adjacent to the pawl hole. On the pull guide surface, a pintle of the pull is mounted across the rear attaching post and a spring body is mounted on the pintle of the pull.
In this spring body, a pawl portion made of a long element bends at an end of the elastic metal platy member, a hook portion made of a short element bends at the other end in the same direction as the pawl portion, and a cut-out hole is provided by cutting a center of a spring piece. The hook portion of this spring body is freely fit into the projection element of the front attaching post through the cut-out hole of the spring body to be hooked thereon, and at the same time, the pawl portion of the spring body is engaged between the teeth of the fastener chain through the pawl hole of the slider body. Then, the cover body holding the pull covers the spring body against the elastic force of the spring body to be supported and fixed on the front attaching post and the rear attaching post.
According to the operation by the slider assembled as described above, when a user picks up the pull by hands, the spring body is picked up against the elastic force of the spring piece, and the pawl portion of the spring body is left from the teeth of the fastener chain. In this state, the slider body is freely moved to the front side so as to couple the tooth rows of the fastener chain. Then, leaving the pull, due to the action of the spring piece of the spring body, the pawl portion is automatically inserted between the teeth of the fastener chain so as to stop the movement of the slider. In addition, if the pull is pulled backwardly, the pintle of the pull rises along the pull guide surface of the slider body and this makes the spring body to be pulled up against the elastic force of the spring piece and the pawl portion of the spring body is left from the teeth of the fastener chain. Then, the slider body can freely move backward to leave from the tooth rows of the fastener chain right and left.
In the meantime, upon forming such a kind of spring piece, when a base portion of the spring piece is cut out obliquely upward directly from a longitudinal middle portion of the elastic metal platy material and a horse-shoe shaped cut-out hole is formed, an oscillation range of the spring piece becomes narrow and it lacks flexibility. Therefore, when the entire spring body is oscillated and this spring piece is fit in the cut-out hole of this spring piece and is hooked in the cutout hole, this involves a problem such that the spring piece does not return to the original state and the automatic stop function of the slider is lost.
In order to solve this problem, for example, in Japanese Utility Model Publication No. 46-35376 proposed by the present applicant in advance, an example of the spring body is disclosed, which is incorporated in the slider of the slide fastener provided with the automatic stop function. The spring body disclosed in this publication has a pair of front and rear oblique plane portions bending obliquely downward back and forth of a long and minute elastic metal platy material; a pair of front and rear leg portions bending vertically downward in connection with respective oblique plane portions; a pair of right and left engaging projections that are protruded at the both sides of the front end leg portion; a pawl portion that is protruded at the rear end leg portion; and a trapezoidal spring piece, which is made by cutting out a portion of the platy material upward and its right and left side faces are tapered, at a lateral middle portion of the elastic metal platy material. In this spring piece, its base portion bends downward more than one step toward the front end side at a position higher than the upper surface of an edged line portion at a rising side of the spring piece of the cut-out hole. The entire spring piece is elongated obliquely upward around the base portion, and a required gap is formed on a flat face with the rising side edged line portion.
In this conventional spring body, the base portion of the spring piece bends and rises upward once, the front end portion of the spring piece is elongated obliquely upward at a required gap with the rising side edged line portion of the spring piece of the cut-out hole, so that there is a gap between the right and left side surfaces and the cut-out hole of the spring piece even when the spring body is oscillated and the spring piece is prevented from being fit into the cut-out hole. In addition, the right and left side surfaces at the front end portion of the spring piece have taper trapezoidal outlines and a flat gap is formed between the rising side edged line portion of the spring piece of the cut-out hole and the spring piece after bending processing, so that it is possible to prevent the rising side edged line portion and the spring piece from overlapping with each other on the oscillation of the spring body.
In addition, another example of a spring body having a pawl portion that is engaged with or released from a portion of tooth rows of a fastener chain is disclosed, for example, in Japanese Utility Model Publication No. 61-27449 and Japanese Utility Model Publication No. 62-490 that are proposed by the present applicant in advance. In the spring body disclosed in these publications, a long spring piece having a predetermined cross section is made of one sheet of elastic metal material by a cutting-out processing.
In the meantime, the spring bodies disclosed in the above-described Japanese Patent Laid-Open Publication No. 10-127313 and Japanese Utility Model Publication No. 46-35376 are made of a metal material such a copper alloy and a stainless steel having a spring property as a long member having a predetermined cross section with its spring piece made in a size corresponding to a width and a length of the cut-out hole made of the metal material. However, since the spring body is a small element of several mm, a width and a length cut out along the outer peripheral end edge of the member become smaller. Therefore, for example, when the spring piece is molded from the metal material having a strong spring property, if the very small part such as the spring piece requires a cut-out processing and a bending processing much, this involves a problem such that the spring piece suffers some cracks during processing or abrasion of a blanking punch blade is hastened. In other words, if the excess force is applied to the front end portion of the spring piece, the spring piece is cut and damaged or it suffers some cracks. Accordingly, it is not possible to improve a processing precision of the front end portion of the spring piece to expect the stability of the figuration and further, there is a limitation in manufacturing many products with a high precision.
On the other hand, in order to acquire the spring body having the spring piece by the cut-out processing that is disclosed in the above-described Japanese Utility Model Publication No. 61-27449 and Japanese Utility Model Publication No. 62-490, a cut-out hole formed along the peripheral end edge of the spring piece is needed separately. Therefore, a width of one sheet of the elastic metal material necessary for cutting out the hole should be set at least larger than the size obtained by adding a width of the cut-out hole to the width of the spring piece. In addition, according to such a cut-out processing, it is impossible to mold a spring body without producing broken ends, broken waste or the like by cutting out, and many scraps such as the broken ends or the like due to cutting out upon molding the spring body occur.
Therefore, such a structure uses materials wastefully and this has limitations in downsizing and miniaturization of the entire spring body. Further, in order to dispose the scraps, various facilities are required and this leads to a defect such that a cost of equipment is escalated and an administration cost is also escalated in connection with increase in the cost of equipment. Moreover, if many minute broken ends fly in air, this may provide health problems.
Generally, when the width of the spring body becomes large, the outline measurement of the pull holding body should be made also larger than the size of the spring body, so that this inevitably leads to growing in size of the entire slider. In addition, in connection with growing in size of the entire slider, since the pull holding body and the slider body are naturally made larger, a cost of manufacturing a mold is increased, and further, the used amount of the material or the like are also increased, so that this involves a disadvantage such that the material cost is high and the slider cannot be manufactured at a low cost. Furthermore, there are problems such that the appearance of the slider is deteriorated in accordance with growing in size of the pull holding body and the slider body and its commercial value is lowered.
Thus, the arts disclosed in the above-described Japanese Patent Laid-Open Publication No. 10-127313 and Japanese Utility Model Publication No. 46-35376 have limitations in mass-producing the spring pieces with a high accuracy depending on the size of the spring body, and according to the arts disclosed in Japanese Utility Model Publication No. 61-27449 and Japanese Utility Model Publication No. 62-490, the sizes of the pull holding body and the slider body are inevitably restricted by the size of the spring body. Therefore, simplicity, downsizing and miniaturization in molding the spring body are strongly requested. If this requests are satisfied, it is possible to effectively use the inner spaces of the pull holding body and the slider body having the same measurements as the conventional cases even when assembling the spring body.
The invention has been made taking the foregoing problems into consideration and a first object of the invention is to provide a slider for a slide fastener capable of reducing a material cost and a manufacturing cost, and capable of realizing a stable and excellent productivity, and a second object of the invention is to provide a slider with an automatic stop function, and its structure is simple and inexpensive, which can be miniaturized while securing a stable and excellent automatic stop function, and in which a spring body is mounted, whereby an excellent exterior design can be acquired.